Loading COMMAND.COM high - the ultimate DOS 5.0 trick... Any of you guys out there real memory freaks or just like to tinker with DOS? Well, here's an original idea for you: load COMMAND.COM high. Not just load it high, but load the primary copy high. Assuming you've got a UMB server (you're using EMM386 or QEMM or something), here's one way to do it... You SHELL command in CONFIG.SYS probably looks something like this: Shell = c:\command.com c:\dos /e:512 /p What if you changed it to look something like this: Shell = c:\command.com /c lh c:\command.com c:\dos /e:512 /p What would that accomplish? Basically, what you're doing is loading a temporary copy of COMMAND.COM and telling it to execute a statement and immediately exit (the /C option). The command just happens to be LOADHIGH COMMAND.COM. Although, the temporary copy gets "stuck" in low memory (/C tells the first copy to exit, but the /P on the high copy makes it permanent, so you can't exit back to the first to release it), your primary copy of COMMAND.COM is loaded high. You computer finishes the boot process as normal and nothing looks different. BUT, things are different. The high copy of COMMAND.COM acts as a doorway to your high memory. Try using a memory mapping utility such as MAPMEM (TurboPower Software). You'll find that the map is not only your low memory, but also your high memory. You'll also notice that any TSR you load from the DOS prompt (even without LOADHIGH) will automatically become resident in high memory. You'll notice a few extra k free down in low conventional, and memory access (compare before and after speeds by looking at CheckIt's Memory Map) in the high area is quite a bit faster. What are the drawbacks? The only problems discovered to date are related to TSRs, especially ones that try to update their status in memory (they load fine, but don't try to change them). They tend to lock up often, however, all major programs that I've tried run smoothly, perhaps even a little faster. Anybody out there that plays with this idea, please drop me a line - I'm interested to see what you come up with. I have an idea of using NDOS (which can load itself high to start with) to bounce the permanent copy of COMMAND.COM off of. That should free up some more low memory. Let me know of any developments you make. Does Microsoft know the potential of doing this? Who's to say... ----------------------------------- Greck S. Cannon SysOp, Split Infinity 919 746-2517 USR Courier HST 14.4k V42bis <*** End of Original File ***>